This invention relates to a method of making drainage/irrigation elements from recycled plastics material. The invention also provides a drainage/irrigation element comprising a bat of recycled thermoplastics material in the form of noodles of agglomerated said material melded together in an open, porous structure.
Various methods of making drainage/irrigation elements from recycled plastics material are known, as are such products.
DE-A-4217739 discloses a drainage soakaway mat made from recycled plastics material. Plastics material is chopped into strips or threads using environmentally friendly and energy saving preparation methods, although what those methods are is not specified. The material is then cleaned and then shaped into a drainage soakaway mat when hot. Again, there is no explanation, in fact, as to how this is to be achieved. After the drainage soakaway mat has cooled down, the strips or threads weld together so that an elastic and solid slab with many hollow spaces, which are the actual drainage organs, forms. As far as the present applicant is aware, no such material as described has been supplied to the market.
FR-A-2706792 discloses a method of granulating recycled plastics by compressing waste plastics in an archimedes screw extruder and pressing through apertures in a die provided with a face cutter that cuts the out put into granules. The only heat of the process is provided by mechanical action imparted on the plastics material, but this is enough to melt and agglomerate the plastics into relatively homogenous plastics pellets. EP-A-1201391 and WO-A-9956925 also describe agglomeration of waste material.
WO-A-0073593 describes a drainage/irrigation element comprising a mixture of thermoplastic, thermoset and fibrous materials melded together by the thermoplastic materials.
It is an object of the present invention to provide a method of making drainage elements from recycled plastics which is both efficient and flexible.